1. Field of the Invention
The present invention relates to a communication system, and in particular to a communication system for allowing a communication terminal to communicate via an access point apparatus.
2. Description of the Background Art
One technology regarding a communication system for allowing a mobile terminal to communicate via an access point apparatus is described in patent document 1 (Japanese Laid-Open Patent Publication No. 2001-345819). The technology described in patent document 1 is regarding an authentication procedure between a mobile station, such as a mobile terminal or the like, and an access point apparatus. Specifically, when the mobile station requests the access point apparatus for authentication, the access point apparatus transmits an authentication response message including a Challenge Text value to the mobile station. The mobile station encrypts the Challenge Text value included in the received authentication response message in accordance with a WEP encryption algorithm, and returns the encrypted value as included in an authentication request message to the access point apparatus. Upon receiving the encrypted Challenge Text value, the access point apparatus decodes the value in accordance with a predetermined method and compares the decoding result with the original Challenge Text value (the value transmitted to the mobile station). When the two values are the same, a user administering the network instructs whether or not to permit the authentication. When the user permits the authentication, a data link is established between the mobile station and the access point apparatus, and then data communication is made possible.
With the technology described in patent document 1, authentication processing is performed on the mobile station, which has requested authentication, using data for authentication. After the authentication processing, the user instructs whether or not to permit the authentication. With this technology, the authentication processing is necessarily performed. Therefore, authentication processing may be performed even on a mobile station that the user will reject authenticating at high possibility. In such a case, the authentication processing is wasted, which reduces the entire authentication processing efficiency and raises the processing load unnecessarily.